Retention means for artificial teeth, gum sections, and the like



R. w. ERDLE RETENTION MEANS FOR ARTIFICIAL TEETH, GUM SECTIONS, AND THELIKE Filed June 29, 1936 j2ue2220n 129257??? METZZQ.

UNITED STATES PATENT OFFICE RETENTION MEANS FOR ARTIFICIAL TEETH, GUMSECTIONS, AND THE LIKE Reine: W. Erdle, Chicago, Ill., assignor toDental Research Corporation, a corporation of Illinois Application June29, 1936, Serial No. 87,951 2 Claims. (Cl. 32-10) My invention relatesto retention means for other tooth supporting part, consequently themaartificial teeth, gum sections and the like. terial forming the plateor other tooth supporting While I shall refer to the invention inconnecpart at times separates or peels away from the tion withartificial teeth in the following genglazed surface of the porcelaintooth and creates 5 eral statement of the nature of the invention, it isan unsanitary condition. 5 to be understood that the invention is not tobe The second scheme above mentioned, namely limited to such use but maybe employed in conof providing the tooth with a cavity havingdefinection with gum sections and the like as will apnite undercuts andpermitting the material of the pear from the iolowing detaileddescription and denture base or other tooth supporting part to thedrawing. fiow into and harden in such cavity, has the 10 In attachingartificial teeth to a denture base objection that the large cavityweakens the tooth or other tooth supporting part it is customary to inproximity such cavity. If such a tooth requires provide retention meanson the tooth for the pur-' considerable grinding, breakage frequentlyrepose of fastening the same to such denture base or sults. In addition,these teeth are also glazed on other tooth supporting part. allsurfaces, and at times the denture material 15 So far, there have beentwo general schemes separates or peels away from the porcelain tooth,for securing the desired attachment, first, by leaving a sp ce for f oand a v to lod e. means of metal pins anchored in the porcelain which,of course, is undesirable. tooth with the exposed ends of the pinsprovided The object of my invention is to provide an arwith rivet headswhich are embedded in the tiflcial tooth, gum section or the like, withim- 20 tooth supporting part and, second, by providing proved retentionmeans for securing satisfactory the tooth with a cavity which is ofre1ativelyattachment to the denture base or other tooth large size andhas definite undercuts and permitsupporting part without the metal pinsand relating the material of the denture base or other tively largecavities about described, as well as tooth-supporting part to flow intoand harden in without the disadvantages and objectionable re- 25 suchcavity. sults due to such metal pin and large cavity forms According tothe first scheme above mentioned, of retention. as a rule two metal pinshave usually been em- Further objects and features and advantages beddedin the porcelain tooth. In the past, platiof the invention will beapparent from the lolnum or platinum alloy pins were used and the lowingdetailed description taken in connection 30 porcelain fuse around thesepins. Precious metal with the accompanying drawing, in which: pin teeth,however, are not very popular for Figure 1 is a rear elevational view onan enthe reason that they are expensive and small ,larged scale 0! ananterior tooth provided with checks occur in the porcelain around thepins retention means embodying the present invenupon firing theporcelain, thus weakening the tion; 35 tooth. The popular method ofanchoring a metal Figure 2 is a vertical section taken on the line pinin a porcelain tooth is by a soldering method. 2-2 of Fi r 1 d S w fr mn ri y. The porcelain tooth is iormed with two small portion of thedenture base or supporting part for platinum collars in the tooth. Themetal pins are the tooth;

4 soldered in these precious metal collars after the g r 3 is afragmentary Section on 91 e y 0 tooth has been fired. enlarged scale,showing the character of the The metal pin iorm of retention has theobjecroughened retention surface of the tooth and the tion of requiringa relatively thick porcelain body manner in which the denture basematerial is at the place where the metal pins are anchored. locked intoeng ement with the undercuts of the Furthermore, the pin itselfprotrudes, and conseretention means; 45 quently adds to this alreadythick dimension of F gure 4 is a perspective View Of a posterior thetooth. This is objectionable because in many tooth provided w retentionmeans b yi cases there is not enough space for the thick the presentinventi tooth and the protruding pins. The cross-section Figur 515 a v rica S n h h a gum Sec- 0 or the porcelain tooth at the place where thetion and plate or denture base part embodying metal pins are anchored isa weak part in the the present invention; and pin tooth, andconsequently pin teeth frequently Figure 6 i a Se i al Similar to Figure2 Showbreak at this location. Pin teeth are glazed all ing a furtherembodiment of the invention. over, and the smooth glazed surface doesnot pro- Referring first to Figures 1 and 2, the tooth 5 vide a goodgrip for the material of the plate or structure therein illustratedcomprises an anterior tooth 5 formed preferably of porcelain. A portionof a denture base, plate, or other tooth structure supporting part, isindicated fragmentarily at 6 in Figure 2. This tooth structuresupporting part 6 may be formed of vulcanite, Celluloid, syntheticresin, or any other suitable or preferred material.

The tooth 5 has a surface I which is embedded in and anchors the tooth 5to the base or supporting part 6. The surface I is roughened and ofgenerally granular-like form to present a rough and preferably unglazedsurface with numerous irregular undercuts, as shown on an enlarged scaleat 8 in Figure 3, over the entire surface I. The material forming thedenture base or tooth structure supporting part 6 is molded upon theroughened surface 1, flowing into .and hardening in interlockingengagement with the the relatively fine and irregular undercuts as shownat 9 in Figure 3.

The tooth 5 is thus very strongly secured to the tooth structuresupporting part 6 over the entire surface 1, as distinguished from thelocalized and less secure attachment provided by metal pins and largecavities as previously described. It is practically impossible for thedenture base or part 6 to separate or peel away from the retention partof the porcelain tooth 5, and consequently a more sanitary denture isassured.

Furthermore, it is thus possible to construct a very thin tooth withoutthickening the same for anchorage therein of metal retention pins or thelike, or for large retention cavities, and the tooth structure is notweakened adjacent the retention means as where metal pins are anchoredin the porcelain tooth or a large retention cavity provided therein.There is no checking of the porcelain such as has resulted where theporcelain is fused around such retention pins. The matter of forming thetooth with precious metal collars therein and soldering the pins in suchcollars is obviated, and there is no weakening of the tooth byconsiderable grinding as has been the case with a tooth provided with alarge retention cavity In Figure 4 I have shown in perspective and on anenlarged scale a posterior porcelain tooth I2 provided with a surface l3which is embedded in the material of the denture base or other toothstructure supporting part not shown. This surface I3 is roughened and ofgenerally granularlike form to present a rough and preferably unglazedsurface with numerous relatively fine and irregular undercuts as in thepreceding embodiment of the invention. The roughened and granular-likeretention means on the surface I 3 in indicated at M.

In Figure 5 I have shown a gum section embodying the retention means ofthe present invention. This gum section consists of one or moreporcelain teeth l5 to which a gum simulating section l6 of porcelain isattached. 'Ihis gum simulating section l6 preferably has a ceramic glazeresembling the gum tissues. The entire gum section, comprising the toothor teeth I 5 and the gum simulating part It, is attached to the denturebase or plate part I8 by a roughened and generally granular-like surfacel9 formed on the gum section l5, I6, similar to the roughened surfaces 1and I3 of the preceding embodiments of the invention and with the sameadvantageous results previously described.

The roughening of the retention surfaces may be produced in variousways. First, small ceramic fragments which serve as retention means maybe baked onto the surfaces "I, I3 and [9 of the green or vitrifiedporcelain tooth structure, The resulting surfaces resemble the surfaceof emery paper. Second, I contemplate treating the green porcelainsurfaces which are to form the roughened retention surfaces withmetallic oxides, minerals or fluxes. The green porcelain surfaces absorbsuch metallic oxides, minerals or fluxes, which results in small localshrinkage cracks or frothing upon firing, and thus provides a roughsurface with innumerable relatively fine and irregular undercuts, Third,a mixture of the tooth porcelain, cork, which is one illustrativematerial which will burn out upon firing, and a ceramic material, whichslightly increases the fusing point of the porcelain and preventsglazing, and materials like Ball clay, finely ground; asbestos; diglycolstearate or a gum, is added to facilitate the application of theretention material. This retention material is applied to the retentionsurface of the tooth or gum section, either in the green stage in thebisque or in the fired condition, and heated to approximately the fusingpoint of the tooth porcelain. The cork, which is in the retentionmixture, will burn out and leave numerous relatively fine and irregularundercuts.

A typical formula for this form of retention material is as follows:

Grains Ground cork 2 Tooth porcelain 15 Ground highly refractory ceramicparticles (such as high fusing porcelain or sillimanite), 15 to 20 mesh15 This is mixed with a liquid consisting of one part of silicate ofsoda and five parts of acidulated water (water to which a small amountof hydrochloric acid is added).

In either case the retention surface which is produced is substantiallythe same as that shown on an enlarged scale in Figure 3. Each form ofretention comprises numerous ceramic projections distributed over theentire extent of the retention surface, and numerous and irregularundercuts as shown at 8 which interlock'with and very securely fastenthe tooth, gum section, or other tooth structure to the denture base orother tooth structure supporting part.

The porcelain retention projections, indicated at 22 in Figure 3, arepreferably unglazed andprovide an improvement over the various forms ofretention heretofore provided. I do not intend, however, to be limitedto an unglazed ceramic retention of this sort, as I have found thatglazed ceramic retention of similar character also provides improvedresults,

As a further embodiment of the invention contemplated within the scopeof the appended claims, the roughened surface 25, similar to theroughened surfaces of the preceding embodiments of the invention, may beformed on a separate thin porcelain piece 26 as shown in Figure 6. Thispiece 26 may be applied to the tooth 2'! or gum section part with thepiece 26 and tooth or. gum section part in green form and baked onto thetooth or. gum section part in the firehardening of such part orotherwise as suitable or desired.

a I do not intend to be limited to the other details shown or describedexcept where the same are expressly recited in the appended claims,

I claim:

l. The method of forming retention means on 75 a porcelain toothstructure which comprises treating the tooth structure with a mixture ofthe tooth porcelain, cork, and a ceramic material which slightlyincreases the fusing point of the porcelain and prevents glazing, andheating the tooth structure with said mixture applied thereto toapproximately the fusing point of the tooth porcelain, whereupon thecork burns out and leaves numerous undercuts.

2. The method of forming retention means on a porcelain tooth structurewhich comprises treating the tooth structure with a mixture of the toothporcelain, a material which will burn out upon firing, and a ceramicmaterial which slight- 1y increases the fusing point of the porcelainand prevents glazing and heating the tooth structure with said mixtureapplied thereto to approximately the fusing point of the toothporcelain, whereupon the material which will burn out burns out andleaves numerous undercuts.

